Downloading/mirroring the TeX Live repository

If you have problems with the network installation, or have several
local machines to install or keep up to date, you may find it helpful to
separate the operations of downloading TeX Live and the actual
installation or update. Thus, “mirroring the TeX Live
repository”. This “repository” contains each TeX Live
package in (one, two, or three) separate .tar.xz files. This
repository is what is used by the regular network installer and by tlmgr for updates.

By far the most efficient method of mirroring is rsync: rsync -a --delete rsync://somectan/somepath/systems/texlive/tlnet/ /your/local/dirHere, somectan is a CTAN
mirror that offers rsync and is nearby to you. The
/somepath is the top-level CTAN directory on that mirror.
Add -v if you want to see the names of the files as they
are transferred.
Add -L if your system does not support symbolic links.
Full rsync
documentation.

If rsync is problematic for whatever reason, you can use wget (or
other tools) to mirror via http or ftp. Here is a sample wget
invocation: wget --mirror --no-parent ftp://somectan/somepath/systems/texlive/tlnet/ /your/local/dirwith the same somectan and somepath as above. (The
--background, --no-host-directories, and/or
--cut-dirs options may be useful. Fykk wget
documentation.)

However, if you are on Windows, to run install-tl-windows
directly you must ensure that all the *.bat, *.dll, and *.manifest files
are executable. Either the mirroring software or the original mirror
often clears executable permissions. Using install-tl.zip may
be simpler.